From Ergo Log
If you replace lab mice’s drinking water with green tea, they live longer. Researchers at the Japanese National Institute for Longevity Sciences discovered this when they did experiments on male C57BL/6 mice. This type of lab mouse often develops cancer of the lymph glands in old age, and like many other rodents is also susceptible to kidney problems.
The researchers used a standard green tea extract often found in supplements. It’s called Sunphenon and is manufactured by Taiyo Kagaku. “It was composed mainly of (-)-epigallocatechin 3-O-gallate (18.0%), (-)-gallocatechin 3-O-gallate (11.6%), (-)-epicatechin 3-O-gallate (4.6%), (-)-epigallocatechin (15.0%), (+)-gallocatechin (14.8%), (-)-epicatechin (7.0%), and (+)-catechin (3.5%)”, the researchers write. They mixed 80 mg in one litre of water and gave it to their mice.
Administration started when the animals were 13 months old. A control group was given ordinary drinking water.
The figure below shows that the maximum lifespan of the mice that drank green tea is 6 percent longer than that of the mice that drank water. The effect is not particularly remarkable. What is more interesting is the reduction in mortality between 20 and 30 months of age.
Humans who have just entered the second half of their life are more likely to die of cancer. One theory is that the immune system starts to work less well, so it doesn’t remove all cancer cells. The researchers speculate that the polyphenols in green tea may help repair this defect.
The green tea extract had no effect on the mice’s weight. In the early days of longevity research, life-extending effects were incorrectly ascribed to because they reduced the subjects’ food intake. As a result the animals lived longer. This was not the case in this experiment.
The researchers admit that they don’t know exactly how green tea works. They say that it’s more important that they have established that green tea does work: “Even if the basic mechanism is not fully elucidated, the confirmation of the present study may provide a rational approach for the nutritional interventions in aging and age-associated disorders in humans.”
Biogerontology. 2007 Oct; 8(5): 567-73.